Hands Free Module (HFM)

B143B-MICROPHONE 1 CIRCUIT LOW





For a complete wiring diagram, refer to the wiring information .

- When Monitored:
With the ignition on.

- Set Condition:
The Hands Free Module (HFM) detects a short to ground or open on the (X712) Microphone 1 IN (+) circuit.





1. CHECK FOR AN ACTIVE DTC

NOTE: Verify the connection of the Rearview Mirror harness connector.

1. Turn the ignition on.
2. With the scan tool, read the active DTCs.

Does the scan tool display B143B-MICROPHONE 1 CIRCUIT LOW as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE HANDS FREE MICROPHONE




1. Turn the ignition off.
2. Disconnect the Hands Free Microphone harness connector.
3. Connect a jumper wire between the (X793) Microphone Feed and the (X712) Microphone 1 IN (+) circuits.
4. Turn the ignition on.
5. With the scan tool, read the DTCs.

NOTE: DTC B143C-MICROPHONE 1 CIRCUIT HIGH should display as active as a result of this test.

Does the scan tool display B143B-MICROPHONE 1 CIRCUIT LOW as active?

Yes

- Go To 3

No

- Replace the Hands Free Microphone.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK FOR THE (X712) MICROPHONE 1 IN (+) CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the Hands Free Module C1 harness connector.
3. Measure the resistance of the (X712) Microphone 1 IN (+) circuit between the Hands Free Microphone and Hands Free Module harness connectors.

Is the resistance above 10K Ohms?

Yes

- Repair the (X712) Microphone 1 IN (+) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 4

4. CHECK FOR THE (X712) MICROPHONE 1 IN (+) CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (X712) Microphone 1 IN (+) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (X712) Microphone 1 IN (+) circuit for short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Hands Free Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.